This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A001478 #37 Nov 14 2022 00:37:49
%S A001478 -1,-2,-3,-4,-5,-6,-7,-8,-9,-10,-11,-12,-13,-14,-15,-16,-17,-18,-19,
%T A001478 -20,-21,-22,-23,-24,-25,-26,-27,-28,-29,-30,-31,-32,-33,-34,-35,-36,
%U A001478 -37,-38,-39,-40,-41,-42,-43,-44,-45,-46,-47,-48,-49,-50,-51,-52,-53,-54,-55,-56,-57,-58,-59,-60,-61,-62,-63,-64,-65
%N A001478 The negative integers.
%H A001478 Felix Fröhlich, <a href="/A001478/b001478.txt">Table of n, a(n) for n = 1..10000</a> (first 1000 terms from David Wasserman)
%H A001478 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>
%H A001478 <a href="/index/Cor#core">Index entries for "core" sequences</a>
%H A001478 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F A001478 a(n) = -n.
%F A001478 G.f.: -x/(1-x)^2.
%F A001478 G.f. A(x) satisfies A(x) + A(-x) = 4A(x^2), A(x)A(-x) = A(x^2), A(x)^2 + A(x^2) = 4A(x)A(x^2). - _Michael Somos_, Mar 23 2004
%F A001478 a(n) = -A000027(n). - _Felix Fröhlich_, Jul 23 2021
%p A001478 A001478 := n->-n;
%t A001478 Table[ -n, {n, 1, 50}] (* _Stefan Steinerberger_, Apr 01 2006 *)
%t A001478 Range[-1, -65, -1] (* _Alonso del Arte_, Oct 06 2013 *)
%o A001478 (PARI) a(n)=-n
%o A001478 (Python) def a(n): return -n # _Michael S. Branicky_, Nov 13 2022
%Y A001478 Cf. A001477 (complement in A001057), A000027, A001489, A130472.
%K A001478 core,sign,easy
%O A001478 1,2
%A A001478 _N. J. A. Sloane_